1. Field of the Invention
The invention concerns a new multi-phase sunscreen agent with improved sunscreen properties.
2. The Prior Art
A multitude of sunscreen formulations are already known that contain certain organic and inorganic active ingredients as emulsions for filtering out (absorption or reflection) UVB radiation (range 290 to 320 nm) and UVA radiation (range 320 to 400 nm). Known organic active ingredients include in particular the derivatives of dibenzoylmethane, benzophenone, salicylic acid, cinnamic acid, 3-benzylidenecamphor, 4-aminobenzoic acid, etc. Known inorganic active ingredients include pigments such as the oxides of titanium, iron, zinc, silicon, aluminum, zirconium, etc. A mixture of organic and inorganic substances that is described as being superior to titanium dioxide is also known (European Patent EP A 588,498).
Published International Application No. WO 94/22419 describes a skin tanning agent where two components are present in separate containers and react when mixed together on the skin, producing a color.
The development of sunscreen formulations has mainly tended toward new active ingredients or a combination of known active ingredients. In general, these are present in emulsions to ensure a good and uniform distribution on the skin, where agglomerations of inorganic pigments have been prevented by surface-active substances.
However, hydrodispersions have also become known that do not contain any emulsifier and are a dispersion of a discontinuous lipid phase (liquid, solid or semisolid) in an external continuous (aqueous) phase. The stability of such an emulsifier-free system is achieved, for example, by creating a gel structure in the aqueous phase with a stable suspension of the lipid droplets in this gel structure. A disadvantage of these hydrodispersions is the required high concentration of UV filter materials and their stickiness.
European Patent EP A 603,080 describes a cosmetic or dermatological two-phase composition that consists of an aqueous phase and a separate oil phase containing alkyldimethylbenzyl-ammonium chloride in the aqueous phase and is suitable for skin care or for removing make-up.
World Patent WO 94/17779 discloses hydrodispersions which are emulsifier-free products to prevent possible irritating effects of emulsifiers (Mallorca acne). The stability of the dispersions is supposed to be ensured by an internal lipid phase with the inorganic pigments and an external aqueous phase.